The present invention is in the field of blast resistant frameworks for windows and in particular it is directed to a method for attaching a glass pane to a profiled sash of blast resistant windows.
Casement windows with which the present invention is concerned typically comprise a rectangular (sometimes a polygonal, arced or the like) framework consisting of a frame anchored within an opening in a wall and a sash swingably mounted thereon with suitable locking means preventing unintended opening of the sash.
The evergrowing threat of chemical/ biological war in some regions in the world, has led to some recent requirements to provide blast-resistant gas-tight windows. Even more so, conventional explosions caused either by explosive charges or accidentally at industrial facilities, also require protecting people within structures by blast-resistant windows. The term xe2x80x9cblast-resistant windowxe2x80x9d indicates on the one hand, that the glass pane of such a window will withstand a blast caused by an explosion and, on the other hand, indicates that the framework is resistant and will deform only up to a restricted limit to prevent injury of people within a room.
Designing blast-resistant windows involves several considerations, namely the durability of the glass pane, resistance of the hinge and locking assemblies, durability of the framework and means for attaching the glass pane to the framework. The present invention is concerned with the latter.
The problem involved with attaching the glass pane to the framework is that most of the blast""s energy is received by the glass pane, that owing to its significant surface area as compared with other components of the window. The outcome is that a majority of bending and shearing forces act between the glass pane and the framework supporting it. Accordingly, it is desired to provide some damping means for absorbing the blast energy in order to prevent portions of the framework or window pane to break or deform in a manner which might be hazardous to individuals in a room.
One solution is disclosed in co-pending Israel Patent Application No. 123980 owned by Arpal Aluminum Ltd., in which there is provided damping means adapted for intentional deformation of profiles so as to absorb the blast""s pressure energy.
However, arrangements as described in that disclosure referred to constructional profile elements adapted for mechanical deformation. Such elements, apart from increasing the overall weight of the framework, are also expensive and more complex in construction.
It is an object of the present invention to provide a new and improved method for attaching a glass pane to a framework of a blast-resistant window in which the above desiderata are fulfilled and in which the above drawbacks are significantly reduced or overcome.
According to the present invention there is provided a blast resistant framework for a window, the framework comprising a frame fitted within an opening of a wall or the like, and a window sash assembly holding a window pane mounted on the frame in a rigid and air-tight manner;
the invention characterized in that the window sash assembly comprises an L-like shaped pane-supporting profile, said profile circumferencing the window pane and having a first leg portion extending along side edges of the pane and a second leg portion extending along peripheries of the window at an inner face thereof; wherein the window pane is attached to the pane-supporting profile by an essentially flexible adhesive material applied at least to the first leg portion of said profile.
The reinforced window pane is preferably a bullet, attack and blast resistant material or sandwich of materials, offering protection against vandalism (physical attack), kinetic energy of bullet and shrapnel, and blast.
Typically, a window with which the invention is concerned is a casement window. However, it should be noticed that the invention is not restricted thereto.
In accordance with a preferred embodiment of the invention, the adhesive material is a Low Modulus Silicone.
In accordance with one specific embodiment, the adhesive material is applied also along the second leg portion of the pane-supporting profile.
By still another embodiment, there is further provided a front-support profiled portion extending along peripheries of the window pane at an outer face thereof. Alternatively, the front-support profiled portion is fixedly attached to the pane-supporting profile.
By another application, the front-support profiled portion is integral with, or fixedly attached to a profile of the frame.
Preferably there is provided a resilient seal member extending between the front-support profiled portion and the window pane, sealingly received therebetween.